1. I can't say much about Windows Email because I never used it. I use AOL since day1 and was always well served with it.
2. The startup programs are easy to manage. Just disable those that you do not want - in fact, other than your AV program, you can disable all. I use WinPatrol
to manage the startups because it has such an easy interface. But you can also do it with msconfig
3. I happen to be very happy with IE8. Maybe you can describe the nature of your problems so that we can try to help. FF is a good browser, but I had no luck with it. Some people also recommend Google Chrome.
4. I would bet a bottle of something that you will like Windows7 after 6 months and never look back to XP - just stick around and make use of the fantastic tutorials on this forum. Maybe you can start with this one
PS: I think bobtran had the same idea - a couple of minutes ahead of me, LOL.